Insulin and Glucagon

Hormones linked to blood glucose

Dr. Turin Chowdhury

Insulin is a familiar word as there are many who suffer from diabetes. But most of us might not have heard of glucagons, which is very much an important substance for our body. The importance of insulin and glucagon are due to their action in maintaining the balance of blood glucose levels in our body. Glucose is a very important element for our body. We need energy for our bodily activities. This energy is derived from glucose. Glucose is the body's primary source of fuel. Whatever food we consume that is transformed into glucose in our body. This glucose is than transported to our body cells by blood to be used as energy source. So without glucose our body will be out of energy source leading to a shutting down of all activities. When we work hard or have not taken meal for long time we feel hungry. This hunger is the state when our body runs short in glucose and needs immediate refueling. In this circumstances when we take food, the food gives supply of glucose and our body glucose comes to a stable situation leading towards the smooth functioning of the body.
   
   Role of Insulin:
   When we take food and glucose is made from the food metabolism, this glucose is than transported to our body cells by blood to be used as energy source. In this phase we need a hormone named Insulin which assists the glucose in the blood to enter in the cells. When blood glucose levels rise, cells named beta cells in pancreas release insulin. Pancreas is an organ located behind our stomach. Without the presence of insulin our body cells cannot take up the glucose from the blood leading to glucose crisis in the body cells for performing activities. If we insulin deficit, the process of glucose metabolism begins working improperly. Instead of being transported into body cells, glucose starts building up in the bloodstream. This situation may occur in two conditions.
   1) When body cells become resistant to the action of insulin. Exactly why the cells become resistant to insulin's effects is still not clearly known.
   2) If there is deficit in glucose production in the body by the glucose producing cells in pancreas.
   These two situations can lead towards the disease condition called diabetes mellitus.
   
   Role of Glucagon
   When there is accesses glucose in our body, this glucose is stored for future use by out body as fat cells. If in any case there is any shortage of glucose in our body and there is no supply available than body goes for the alternative way to fulfill the deficit. When blood glucose levels fall, cells named alpha cells in pancreas release glucagon. When blood glucose is high, no glucagon is secreted from the alpha cells. Glucagon has the greatest effect on the liver although it affects many different cells in the body. When glucose levels are low our liver releases the stored glucose into the bloodstream to keep blood glucose level within a normal range and Glucagon's main function is to cause the liver to release stored glucose from its cells into the blood.
   
   Pancreas: the home
   The pancreas is an elongated, tapered organ inside our body. It is located across the back of the abdomen, behind the stomach. The right side of the organ is called the head and is the widest part of the organ and lies in the curve of the duodenum, the first division of the small intestine. The tapered left side extends slightly upward and is called the body of the pancreas and ends near the spleen and where it is called the tail. The pancreas has digestive and hormonal functions:
   * Digestive function: From pancreas some enzymes are secreted which take part in the food metabolism of our body. These enzymes help break down carbohydrates, fats, proteins, and acids in the duodenum.
   * Hormonal function: The hormones secreted by the pancreas are insulin, glucagon and somatostatin. We already have known that insulin and glucagon regulate the level of glucose in the blood. Somatostatin can inhibit both insulin and glucagon secretion.
   
   Glucose level: insulin and glucagon
   Our body requires that the blood glucose level is maintained in a very narrow optimal range. Our body tries to maintain the blood glucose normally between 70 mg/dl and 110 mg/dl. Blood glucose levels below 70mg/dl, is called "hypoglycemia". A blood glucose level of 180mg/dl or more is called "hyperglycemia". If the blood glucose is lower than optimal then our body tries to bring it up to the optimal level. Similarly if the body glucose level is higher than the optimal level then our body tries to bring it down to the optimal level. So according to the body glucose level, body decides which one to secrete, insulin or glucagon? After a meal, the amount of insulin secreted into the blood increases as the blood glucose rises. Similarly, as blood glucose falls, insulin secretion by the pancreatic islet beta cells decreases. On the other hand, glucagon is secreted by the alpha cells of the pancreas when blood glucose is low. As for example, blood glucose is low between meals and during exercise. So for compensating the need of the body the glucoagon is secreted. Contrary to that, when blood glucose is high, no glucagon is secreted from the alpha cells. So we see that the insulin and glucagon secretion is coordinated. Consumption of carbohydrates triggers release of insulin from beta cells.
   Alpha cells become inhibited and cease to secrete glucagon. Opposite happens when we have enough glucose supplied to the body. Major control of blood glucose levels is achieved through actions of the hormones insulin and glucagon. The slightest rise in plasma glucose leads to a decrease in glucagon secretion and an increase in insulin secretion. The reverse occurs when plasma glucose levels fall. Maintaining this balance is very important for our body and any situation leading to the imbalance create disease condition.

^ TOP OF THIS PAGE ^ MAIN PAGE

Pakistan scene: Mian Sahab's
Shortcoming Show

Saad Quasem

The media this week has widely covered the soap-opera being staged in Pakistan. As the regime of Musharraf sinks deeper into the swamp, the deposed former premiers are on the verge of return. It is unnecessary to define and elaborate on the brief return and quick exile of Mian Muhammad Nawaz Sharif as enough is being said. The legality of this issue and the future of Pakistani politics shall be dissected by those fit. However, if politics is set apart the drama as a whole is quite hilarious. Throughout the game play Mian Saheb's aplomb is literally no different than that of a soap-opera.
   Before boarding a PIA flight to Islamabad, Mian Saheb arrived at Heathrow with a convoy of forty vehicles. As Heathrow transformed into a Muslim League stronghold, Mian Saheb's morale was being uplifted. Media men were busy taking his picture as he walked with the British-Pakistani MP Lord Nazir and the infamous PPP leader Mustafa Khar. It was at this time, his brother and left-hand Mian Shahbaz Sharif was asked not to board the flight and the brothers tearfully parted. Mian Shahab stated that if he is arrested "it would be a small price to pay for democracy." Benazir had returned from the same airport 21 years ago to fight another dictatorship of which Mian Shaheb was an integral part as the Chief Minister of Punjab. Nevertheless, his goal was to receive a heroic welcome as Benazir did two decades earlier.
   BBC reporter, Owen Barrett had been traveling with Mian Saheb and his entourage. He said the ex-Prime Minister seemed very cheerful. He had even been relaxed enough to sleep throughout most of the eight our flight. During his waken hours he expressed total confidence in the Pakistani government, regarding his safe return to Lahore. He provided interviews and held political meetings onboard as well and throughout no sign of worries was in sight.
   Mian Saheb's worry turned apparent when the plane touched the tarmac. His supporters clapped and screeched on top of their lungs "Pakistan Zindabad, Nawaz Sharif Zindabad, Go Musharraf!" and other such slogans. Nevertheless, the sight of hundreds of uniformed men scared him off. His face fell and his eyes drooped. The pictures published in the last few days, shows his fallen image as compared to the boosted ones in Heathrow a few hours back.
   Obviously he had been seated in First Class, upon landing Mian Saheb ran to the middle of the aircraft and positioned himself in the middle seat of the middle aisle of Economy with two of his die-hard supporters beside him. That certainly did not help him in anyway. Upon notice of his arrest, he again said "The happenings show that Musharraf has not learnt a lesson as of yet."
   As he disembarked the aircraft, he was taken to the "Rawal Lounge" of 'Pindi airport. With his fallen face he ordered tea. Before a butler could serve the tea, Mian Sahab was put into another aircraft and loaded to Jeddah.
   This drama has existed in Pakistan since its birth. All the civilians who have reigned over the nation have been imprisoned, therefore, it is nothing new at all. Such drastic exile is new. The future will speak for itself. At the moment, all we can do is feel bad for Mian Saheb. Earlier he mentioned that all luxuries in life had been granted to him, but his desire is to "live in the soil, amidst his people." At the moment all we can do is feel bad for him.

^ TOP OF THIS PAGE ^ MAIN PAGE